import java.util.Scanner;

public class Main6 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        double M = in.nextDouble();
        double init = in.nextDouble();
        double finalT = in.nextDouble();
        QCalculator qc = new QCalculator();
        System.out.printf("%.2f", qc.calQ(M, init, finalT));
    }
}

/* 请在这里填写答案 */
class QCalculator {
    public double calQ(double M, double initTemp, double finalTemp) {
        // 在这里实现这个函数
        double Q = M * (finalTemp - initTemp) * 4184;
        return Q;
    }
}

